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69.113.13.131
In Reply to: RE: The new Genelex Gold Lion KT-77 posted by musetap on July 04, 2008 at 11:50:06
Musetap,
How well matched are the tubes for current draw? Do you have a way to measure that in your setup? I only ask because I was just checking that seller's feedback and saw your comments? I really need tightly matched pairs as the amp's I plan on using them in, Fairchild 255As, have no DC balance provision. Thanks if you can comment!
s.l.
Follow Ups:
I got a platinun matched quad, apparentely they are supposed to be matched in the factory, not the dealer, but only 2 where matched, one lower, the other higher, 10 mA difference on my amplifier...
Antonio Melo Ribeiro
I have posted MANY times about the inconsistent and often marginal to poor "factory" matching. Most (not all, but a large majority) eBay sellers sell "factory matched" tubes.First off it is NOT done at the factory, it's done here in the US by the importer. And the "Platinum" designation is meaningless. A few years ago they offered two levels of matching, a "quick match" for lack of a better term, and a higher grade match that included a 24 hour burn-in. The "quick match" went away, and the remaining match was designated "Platinum".
I have also written many times that the "factory" match is based on plate current only. This means that variations in screen current are not accounted for, and since in the vast majority of amps we measure cathode current (which equals plate and screen current combined) the screen current variations are a significant error factor.
10 ma difference is not unusual, I often see more than that.
For the record, I match at real operating voltages, and I match based on cathode current, not plate current only. And (in defense of the importer) I measure each tube's characteristics one at a time, and match tubes that way. They couldn't possibly do that in the quantities they need to do.
...
Antonio Melo Ribeiro
Hiya, not sure about the matching and I have no way to test that. My amp is easy to bias and not finicky, so I'm pretty casual regarding how closely tubes are matched.
The seller I bought from "may" be able to help you with the info you need. I've bought from him before and he is quite accommodating. There was also another dealer on eBay selling these tubes- ctech-electronics-store - and it looks like they provide more accurate numbers regarding matching. I have not dealt with them though they have very good feedback.
As these tubes gain more of a market I'm sure you'll be able to find a dealer that can closely match some for you, but check with Jason and see if he can do so.
2 more hours of listening today was the best I could get in and... these are great sounding tubes, they really draw you into the music.
"...You're all welcome to stay for the next set...we're going to play all the same tunes, but in different keys..." -Count Basie
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